10 AET. 8. H. YABE. 



tion of the age of the flora ; only characteristic of the Rajmahal 

 group " ; but the subsequent discovery of the genus in the fossil 

 flora of many other lands has led A. C. Seward^^ lately to make 

 a short but interesting contribution on the history, time range, 

 and distribution of the genus, accompanied by an important 

 article upon the plant geography of the Jurassic age. Indeed, 

 it was by the occurrence of this plant in the Naktong flora 

 that the present writer was able to draw the conclusion that the 

 deposit is of the Mesozoic era and most probably of the Jurassic 

 age. 



The species of the genus hitherto known, according to 

 Seward, number only three : — 



1. D. falcatus Oldham. 



Kajmahal series of the Kajmahal Hills, and upper 

 Gondwana of the Madras coast, India. 



2. D. falcatus Oldh. var. distans Yok. 



Tetori series of Japan. 



3. D. falcatus Oldh. var. grossinervis (Yok.) 



Tetori series of Japan. 



4. D. Johnstrupi Nath. 



Liassic or Rhaetic bed of Born holm. 



5. D. Hawelli Seward. 



Lower Estuarine of Marske, Yorkshire, England. 

 As is seen from the above enumeration, this genus is surely 

 known from the Jurassic. In strata older or younger than the 

 above, it has not yet been known to occur. 



]) A. C. Sewiiid : Occurrence of Dir.lyozamitei> in England, and on European and Eastern 

 Mesozoic Floras. 1903. 



